Preheat the oven to 180 degrees Celsius. Line two muffin tins with paper liners and set aside.
In a small mixing bowl, whisk together the flour, hazelnut meal, baking powder, and salt.
In separate bowl, combine sugar, butter, eggs and vanilla, and whisk on medium-low until smooth. Alternately add the flour mixture and milk, beginning and ending with the flour. Mix until fully combined.
Scoop the mixture into prepared cupcake liners and bake for 20-25 minutes or until a wooden skewer comes out clean.
To make the frosting, beat the butter with a hand mixer on medium-high speed until smooth.
Add the Nutella and salt. Continue to beat until incorporated, for around 2 minutes.
Add 1 cup of sifted icing sugar, beat on medium-low speed until most of the sugar is moistened.
Gradually add the remaining sugar until the frosting is the desired texture, beating on medium-low speed until fully mixed.
Add the thickened cream and beat on medium-high speed until light and fluffy, for around 2 minutes. Scrape down the sides of the bowl as needed.
Pipe a generous swirl of frosting on top of the cooled cupcakes.
Sprinkle roasted hazelnuts over each iced cupcake and then gently place a Ferrero Rocher on top. Enjoy!